Is this the correct syntax for an Informix update?
update table1
set table1.code = 100
from table1 a, table2 b, table3 c
where a.key = c.key
a.no = b.no
a.ke
your syntax error is table1.code
set table1.code = 100
change this into
set a.code = 100
Full code
update table1
set a.code = 100
from table1 a, table2 b, table3 c
where a.key = c.key
and a.no = b.no
and a.key = c.key
and a.code = 10
and b.tor = 'THE'
and a.group = 4183
and a.no in ('1111','1331','1345')